Sounds like a total scam. This is why I stick to the big name phone recyclers. I bet they only send their trust pilot links to customers who are paid the full price too.
One time with another company, I had reason to contact them two times over two separate issues in two days. I was only given their trust pilot link when they resolved my question to my satisfaction, I didn’t get given it the other time!
They have far too many five star reviews on trust pilot. Rule of thumb - ignore 1 and 5 star reviews and see what you are left with.